Jonathan Osborne (1794-1864) and his recognition of conduction aphasia in 1834.

In 1833 an accomplished 26-year-old linguist suffered a non-paralytic stroke. After he recovered, though he could utter a variety of syllables with ease, he spoke an unintelligible jargon that caused him to be mistaken as a foreigner. He was examined repeatedly over the course of a year by Jonathan Osborne (1794-1864), a Dublin physician and professor of materia medica, who found that the patient understood whatever was said to him, that he could read and write fluently, but had difficulty repeating words read to him or in reading aloud. Osborne recommended that he learn to speak English, his natural language, de novo and over 8 months measured his considerable improvement. To explain the patient's singular difficulty in repeating spoken words Osborne argued it was 'highly probable that, having been conversant with five languages, the muscular apparatus ranged among them, forming a kind of polyglot jargon [that was] wholly unintelligible' and the patient was 'unable to penetrate into and select the contents of the store according as the [words] were required'. The discrepancy between comprehension and repetition was later termed conduction aphasia.